Brake mechanism



u I 1,616,241 Feb 1 1927' l` H. A. TUTTLE BRAKE MEICHANISM Filed May 9. 1925 Patented Feb. 1, 1927.

HENRY A. TU'ITLE, OF UPTGN, MASSACHUSETTS.

Application filed May 9,

'l` his invention relates to brake-mechanisms of the type having` a rotatable brake drum and a flexible resilient band which encircles and is adapted to be contracted about the drum by actuating mechanism which engages the proximate ends of the brake band. The actuating mechanism for a brake band of the type above set forth usually includes cooperating and over-riding cam members.v This type of mechanism ordinarily requires a substantial amount of power to operate 1t, over and above that actually required to contact the brake-band, and the co-acting cam surfaces are subject to rapid wear.

An object of this invention is the provision of brake-actuating mechanisms in which the power-loss is reduced and which is relatively free from wear.

A further object is generally to improve the construction of brake mechanisms.

F ig. 1 is an end elevation of a brake-mechanism embodying the invention.

Fig. 2 is a plan view of Fig. 1.

Fig. 3 is an enlarged plan detail partly in section, of a portion f the actuating mechanism.

Fig. l is a front view of one of the actuating discs, and illustrating the disposition of the strut-pin recesses therein.

Fig, 5 is a plan view taken along line 5)-5 of Fig, 1l.

Fig. 6 is a detail illustrating` the application of the invention to an internal brake mechanism.

As here shown the brake mechanism includes the brake-drum 10 xed to the rotatable shaft 12. A resilient brake-band 1st encircles said drum and is provided with two proximate and approximately `radially-outstanding end-portions 16 and 18. vSaid endN portions are adapted to be forced inwardly toward each other by the actuating mechanism embodying the invention, whereby to contract the band into frictional contact with the drinn. 1When the pressure on the bandends is released, the band is adapted to expand, by its inherent resiliency, away from engagement with the drum.

The brake-actuating mechanism includes a shaft 2O which is passed loosely through the band-ends 16 and 18 and extends in opposite directions therebeyond. The extended ends of said shaft are received in and are Xed by keys 22 and ll, or other suitable means, to the ends of arms 9X3 and 28 ef an i925. Serial No. 29.205.

operating yoke which straddles and is vspaced from the band ends. Suitable mechanism 30 is pivoted to the fre-e ends of said arms whereby to rotate said shaft 2O in its bearings in the band-ends 16 and 18 and effect the operation of the brake.

Means are provided which are adapted to be actuated by the rotary movement of said shaft 20 to contract the brake band. Said means include discs 32 and 84%, which discs are ef square or other non-circular forn'ratiou and yare disposed loosely between ribs oa of the brake-band, in which position they are restrained from rotation by engagement with said ribs. rllhe lower faces 32a of said discs may be of approximately spheroidal formation, and the cooperating faces 16a of the band ends may be complementally formed whereby to provide a self-alignin engagement between each disc and the brake band. Cooperating and actuating discs 3T and 38 are disposed on said shaft 20 adjacent said fixed discs and are fixed to said shaft by said keys 22 and 24. Each set of discs, as

and 87, and 34 and 38, have their proximate faces formed with a plurality of recesses Ll() and l2 therein. Said recesses are disposed in the faces of the discs at approximately equal distances from the center of the discs and are tangential to the radii of the discs. Preferably the recesses are equiangularly disposed in the faces of the discs. The recesses l0 and l2 in a set of discs are adapted to be complemental to each other, and each pair of complemental recesses is adapted to forma slot approximately onehalf of which is in each disc. The recesses may have any suitable shape but preferably are of such shape as to form cylindrical slots, as shown. The axes of the slots are arranged to lie transversely of the faces of the discs, and thereby of the plane of rotation of said discs. Vhen the brake-band is in its expanded position, or out of operative engagement with the brake-drum, it is adapted to support its discs 32 and 34 in positions approximately in contact with the cooperating discs 37 and 38, as shown in lfig. 1.

Strut-pins i4 are received in the slots and are adapted to lie loosely therein. Said pins are here shown as cylindrical and, preferably, are formed with convex heads 46. The dimensions of said pins are such that the similar ends thereof he mainly in one disc while the opposite ends lie mainly in the cocperatlill) All@ lll

ing disc, as illustrated in Fig. Preferably the pins are somewhat shorter than the'slots they occirpy7 where-by to permit a certain reedoin oit lnoveinent ot the actuating' yolic, for adjustments or otherwise, without actuating,T the brake-band.

As thus ar "anged, when the shalt 2() and the discs 3T and 3S are rotated in a counterclockwise direction, the. recesses in said discs' are displaced for register vith the coinplej inentaiy recesses in the discs 32 and 3l carried the brake-band, and the end-walls ot theV recesses are brought up against the ends ot the strut-pins ill. A further rotary nieveincnt ot the shaft 20 and discs 37 and 38 in theV saine directioir to` tilt or straighten the pins, as illustrated iu Fig'. 3, and there by to 'torce the'ends ot' the breite-band inwardly toward each othenI whereby the contract the band about the brake drum.

The discs and 33; may slide in their seats onV the band-ends` to compensate for any changes otangular position of the band ends, during the settingof the brake.

The frictional engagement between the parts ont the niechanisn'i is limited. to the ends ot the strut-pins and to the end-walls ot the recesses. rihe amount of movement between the surfaces is relatively sinall so that the power loss in and wear on the mechanism is relatively small.

Pressure is exerted on the pins at all times when the niechanisin is being operated either dueto the rotation ot the shaft to set the brake, or due to the elasticity of the brake-band, when the mechanism is being moved to release the brake. Consequently the strut-pins are held in their slots against possibility of escape. lVhen the brake is released and the mechanism is in an operative posi-tion7 the pins are loose in the slots, but the walls o't the slots are. adapted substantially Y to enclose the pins and confine thein against escape troni the slots.

The strut-pins acting on opposite ends ot the bralteband are inclined in opposie directions as illustrated in Fig'. l, whereby the band-ends are inoved ini'rardly toward each other when the shaft i0 is rotated.

lnA the application oi' the invention to an internal3 or epandingw brake n'ieehanisni an actuating?,- plate 3i may be disposed between the omgosing ends o't the braliescctions lo and ltl which sections are normally drawn inwardly, and a way troni the brake drinn ltl by the spring` ll'. A plate E52 may be connected with the end ot the brake-section lo by a tongue ou the plate which extends into a` groove in the section. Said plates are grovided` with the recesses and strut pins as heretofore set forth. A pivot screw l?) may be screw-Threaded in the brake-section 18 and entend into a cupped recess in` the middle ot the lower tace ot the actuating plate 37a and serve to hold said plate in position and also as a` eelt-adjusting seat ttor said plate. Adjustments to con'ipcnsate. tor the wear of the brake lining may be made by advancing said screw iu an obviousinanneir. iii-n. actuating arni 26" niay be integral with said actuating' plate.

is thus arranged, the rotation of the actuating plate in the proper direction torres the liirale-sections outwardly to set the brake., the actuating plate following the outward movement ot the section i8,

rl`he construction may be otherwise inedilie-d without departingtronrthe. spirit oit the invention.

l claiiu.:

l. l'lialie mechanismy including1 a brake drinn, a. resilient brake bandencirciing said drinnv and having` proximate end-portions adapted to be nioved inwardly towardfeach other to contract the band about the drunp and' brake actuating ineclia-nisn'i including); :i shaft passed loosely through said end-portions band-plates carried by the remote tacos ot said end-portions, actiiiating plates carried` by said shaft in nornial approximate contee with Said? band-plates, sai/d. plates having recesses in their proximate faces vfhich cooperate to form inclined pin-enclosing slots, strut-pins received loosely in the slots of cooperating plates, and inea-.ns to rotate said actuating` platesl whereby i to straighten saidi strut-pins and thereby torce the end-portions of said band inwardly.

2. Brake mechanism including a brake drinn, a resilient brake band encircling said drinn and having' a free endportion,v and ineans to contract said band about said drinn including a plate carried by the end-portion o said band, a shaft passed loosely through said end-portion and plate, an actuating plate disposed on saidY shatt in normal ap-` proximate contact with said band-plate, said plates'having a plurality oitl slots in their proximate faces which cooperate to forni inclined piirenclosing slots7 aV plurality o't strut-puns disposed loosely in said slots and in both plates,4 and inoans to rotate said :ictuzitinpplate7 whereby to straighten said strut-Inns and exert a pressure on said brakeband.

il Brake n'iecl'ianisin including the coinbination ot two plates, :i brake-pand conplate.: and arranged uected with one ot sai.

to urge said plates inlo noxiuiatc ieialioii.

said plate having opposed recesses therein which cooperate to iorin inclined slots7 inclined strut-pins received loosely in .said slots and having siniilar end-portions disposed niainly in one plate. and their opposite end-portions disposed inafinly in said other plate, and nieans to rotate one plato relative to the other, whereby to straighten said strut-pins and apply pressure on said brake band.

Ll. The combination of two cooperating CII plates, yielding means to` urge said plates toward a normal proximate position, said plates having cooperating recesses therein which normally register to form substantially closed inclined slots between the plates, inclined strut-pins received loosely in said inclined slots and having their similar end-portions .disposed mainly in one plate and their opposite end-portions dispoficd mainly in the other' plate, and means to rotate one plate relatively to said other plate. whereby to straighten said strut-pins and forcibly separate said plates in an axial direction against the action ot' said yielding means.

lrake actuating mechanism includingI the combination of a rotatable shaft, a plate asoca-ted with the brake mechanism and arranged lor axial movement along said shaft. an actuating plate disposed adjacent said lirst plate and having a connection with said shatt whereby it is arranged for angular movement and strut-nicmbers extended between and having pivotal connections with said plates.

(l, Brake actuating mechanism including the combination oit a shaft, a plate associated with the brake mechanism and arranged for axial movement along said shaft, an actuating plate disposedadjacent said Erst plate and arranged for angular movement, strut-members extended between and having pivotal connections with said plates and inclined against the direction of angular movement of said actuating plate, and means including the brake mechanism to urge said plates constantly toward each other.

7. Brake actuating mechanism including the combination of a shaft, a plate associated with the brake mechanism and arranged tor axial movement along said shaft, an actuating plate disposed adjacent sai-d lirst plate and arranged for angular movement, and strut-members received in recesses in and extended between and having pivotal connections with said plates and inclined aga-inst the direction ot angular movementot said actuating plate, said strut-members having a lost-motion. connection with said plates.

8. l'ralre actuating mechanism including the combination of a shaft, a plate associated with the brake mechanism and arranged for axial movement along said shaft, an actuating plate disposed adjacent said first plate and arranged for angular movement, and strut-members received in recesses in and extended between and having pivotal connections with said plates and inclined against the direction oit angular movement of said actuating plate, said strut-men'ibers being loose in said recesses whereby to permit a substantial angular movement of said actuating plate independent of axial movement of said cooperating plate.

9. The combination of a rectilinearlymovable plate, an adjacent angularly-movable actuating plate, means to urge said plates toward and into normal contact with each other, said plates having cooperating inclined recesses therein, and strut-pins rcceived in said recesses and inclined against the direction ot' angular movement ot' said actuating plate. i

10. The combination of a rectiline movable plate, an adjacent angularly-movable actuating plate, means to urge said plates toward each other, said plates having eo-operating inclined recesses therein, and strut-pins received normally loosely in said recesses and inclined against the direction ot' angular movement of said actuating' plate.

11. In a device ot the class described, the combination ot a pair ot cooperating plates, one arranged for axial and the other for angular movement, inclined strut-members interposed between said plates whereby an angular movement ot one plate cil'ects an axial movement of the other plate, and means including said strut-members providing a lost-motion operative connection between said plates, whereby one of said plates can be moved independently of said other plate.

12. In a device of the class described, the combination of a pair of cooperating juxtaposed plates one arranged for angular and the other for axial movement, each plate having inclined recesses therein, means supporting said plates movably in such relation that normally corresponding recesses in both plates are in register to form inclined-slots which occupy both plates, strut-members received loosely in said slots, and means to rotate said angularly-movable plate, whereby to straighten said strut-members and separate said plates.

13. In a device of the class described, the combination of a pair of cooperating juxtaposed plates one arranged for angular and the other for axial movement, each 4plate having inclined recesses therein, means supporting said plates movably in such relation that normally corresponding recesses in both plates are in'register to form inclined-slots which occupy both plates, strut-members received loosely in said slots, said strut-members being substantially shorter than the length of said slots, whereby said angularly movable plate can be moved a substantial amount free from operative engagement with said strut-members.

14. Brake actuating mechanism including a brake band having proximate and free end-portions, an operating shat't extended loosely through said end-portions, two sets of pressure-plates surrounding said shaft and disposed adjacent the remote faces of said end-portions, one plateV of each set havarlying anonrrotatable connection with its band end andi the other: plate having a driving connection with Vsaid shaft, theplates of each setrhaving registering recesses therein which are approximately tangential to a common diameter andY are transversely disposed on said: diameter., Ystrut-pins received loosely. insaidy reeesses and means to rotate said sha-ft, whereby to tilt said pins and contract the bralteband;Y

15. Brake n'iechanism including a brake band having a free end a, eelt-seating engagement with'` said4 band-end and means to restrain it -trom rotation.- on said band, an operating plate disposed acljacent said band-plate7 both plates having registeringreeesses therein, strut-pins re ceived in said recesses and disposed angsth la-rly in both plates, and means to rotate saidjy operating Vplate in. a direction to. tilt plate having a reife-,241

said. st1'ut.-pi11s, whereby to separate said plates and contract said brake band;

16. The combination of. a yielding,1V mem ber, plate-having a self-aligning. bearing engagement and a nen-rotating` connection With said member, anoperating platerotatably su pport-e di in proxmaterelation with said first plate, both plates having normally registering recesses therein which are ange,r larly inclined to the direetion'ofv rotation otsaid operatingy plate, strut-pins received ini said recessesand adapted -for pivotal;y engagement with both` plates, andy means to rotate said opemtineY platein a direction to tilt said strut-pins and move said yielding member.` r

In testimony whereohl have signed my name to this speciiieation;

HENRY A. TUTTLE. 

